PDF: Add support for reading and writing extended (XMP) metadata calibre can now read and write XMP metadata from PDF files. This means that all metadata that you can create in calibre, including custom columns, can be stored in the PDF files. It is also useful when importing PDF files created by some academic publishers, that sometimes have good XMP metadata, such as DOI identifiers, tags and so on.

Edit Book: Allow typing arbitrary unicode characters with the keyboard in the editor To use this feature, just type the unicode code number and press Alt+X. For example, to get the character ÿ type ff and press Alt+X. Closes tickets: 1280868

Edit book: Some performance improvements for the syntax highlighter that should make the editor noticeably more responsive while typing inside large HTML files.

Bug Fixes

Edit book: Fix an error that occurs if more than 100 checkpoints are created. Closes tickets: 1282583

Edit book: Workaround bug in Qt causing crash on deleting bottom most file in the Files Browser on linux

Edit book: Workaround for bug in Qt that caused extra null bytes to be appended to the end of the file when saving if the file contains non-BMP unicode characters.

Edit book: When autofixing file extensions <-> mimetype mismatch, if the file in question is in the spine, change the file extension rather than the mimetype, as that is more likely to be the correct fix.

Fix the Similar Books menu items failing to find similar books if the target book has a quote in its metadata. Closes tickets: 1280606